You can also see the difference on the Blog Stats page of your dashboard. In the right column, there is a list of top posts and a list of top clicks.

Most of my top clicks are image files, but with what raincoaster has said, it makes me wonder why anyone would use the Top Clicks widget. Isn't that like saying, "Hey, want to find something interesting somewhere else? Try these! Now go away!" ?

Yes, in the daytime. And I have no idea why you'd want to advertise them in the sidebar; apparently people want to know this stuff and boast about it. Me, I'm all for making people click all over my blog before leaving. If I had enough duct tape, I'd tape their heads to the monitor. But that's just me.